非谓语动词--之动词不定式(to-do)的用法

非谓语动词之动词不定式（todo）的用法非谓语动词是指在句子中不是谓语的动词，主要形式有：不定式、动名词和分词（现在分词和过去分词）。1.“todo”动词不定式的变形原形进行式完成式完成进行式todo(not)tobedoing(not)tohavedone(not)tohavebeendoing动词不定式的动作与谓语动词同时发生（或几乎同时）或发生在谓语动词之后谓语动词动作发生时，动词不定时的动作正在发生动词不定式的动作发生在谓语动词或特定时间之前动词不定式的动作在谓语动词动作之前，且一直在持续2.动词不定式的用法（1）充当主语（一般会用it当形式主语）Toswimhereisdangerous.=Itisdangeroustoswimhere.TopassthisEnglishexamisunlikely.=（2）充当表语（多数情况下，可以转换成动词不定式做主语）MyjobistohelpwithyourEnglishlearning.TohelpwithyourEnglishlearningismyjob.（3）充当宾语（只能做某些动词的宾语，一般不做介词的宾语；有时用“it”做形式宾语）Idecidedtoattendthismeetinglastnight.Ifinditnecessarytolearnaforeignlanguage.注意：当以下动词欲接动词作宾语时，只能跟不定式作宾语。decide,determine,learn,wish,hopeagree,plan,pretend,dare,refuse,failprepare,try,manage,help,promiseoffer,beg,demand,afford,arrange,besupposed（4）充当宾语补足语Ipersuadedhimtomakeaspeechinpublic.注意：在感官动词／使役动词／help后（see,hear,watch,notice,make,have,let后不定式做宾补时，可省略“to”）Isawthemhaveadisagreementonwhoshouldsweepthefloor.（我看到了他们争论的整个过程）但，感官动词后面也可接Ving形式，表示正在进行。Isawthemarguingaboutwhoshouldsweepthefloor.（我看到他们正在争论谁该扫地，并不一定看到了整个过程）（5）充当状语（目的，原因，结果状语，其逻辑主语与句子主语一致）Iwrotehimalettertofurtherexplainthismatter.（目的状语）I’msorrytobotheryou.（原因状语）Hequeuedforhoursattheboxofficeonlytofindthattheshowwassoldout.（结果状语，only+tofind/realize/discover表示出乎意料的结果）（6）充当定语（不定式作定语，要放在所修饰的词的后面）Ihavealotofdishestowash.Doyouhaveanythingtosay?Thereare3questionstoanswer.（7）一些固定句型中不定式省略“to”hadbetterwouldratherdo…thando…whynotdo“except/but”有“do”无“to”，有”to”无“do”havenothingtodobutdo…doeverythingbut/excepthavenochoicebuttowantnothingbut/exceptto（8）当两个或多个作用相同的不定式并列（and/or/than）时，通常只保留第一个不定式的“to”.Hetoldmetostaythereandwaitforhim.It’seasiertopersuadepeoplethanforcethem.Totryandfailisbetterthannottotryatall.（否定式中“to”不能省略）习题：1.It’sgreat________(hear)thisnewsthatChinateamwonthematch.2.Hepretended________(sleep)whenhisyoungerbrothercamein.3.Weagreed________(meet)herebutsofarshehasnotturnedupyet.4.Althoughregularexerciseisveryimportant,it’sneveragoodidea________(exercise)tooclosetobedtime.5.It’sgoingtorain.You’dbetter________(bring)theumbrellawithyouwhengoingout.6.Youdon’thavetorunfastforlong_______(see)thebenefit.